PARAMETERS AFFECTING THE OUTDOOR NOISE BARRIERS EFFECTIVENESS - SIMULATION WITH SOUNDPLAN
Abstract
Abstract: The article presents design principles of sound barriers and an assessment of the acoustic parameters that can influence their efficiency. It was studied how the acoustic absorption coefficients of the noise barriers coupled with the noise emission characteristics of the noise sources influence the values of the noise level at the receiver. For this, with the help of the SoundPlan software package, it has been shown that for noise sources with the same acoustic power values and sound barriers of the same size, the values of the sound pressure level at the receiver location differ significantly depending on the spectral characteristics of the acoustic emission and by the sound absorption coefficients of the sound barriers. It has been shown that the sound absorption evaluation index - DLα - of sound barriers does not always reflect the actual performance of the sound barriers, there being situations where, for industrial noise sources, a sound barrier having DLα = 8 dB will lead, at the receiver point, to lower values of the sound pressure level than a barrier with a higher value of this index - DLα = 10 dB. As soon as the DLα index is given for the normalized traffic noise spectrum, not for industrial noise spectra, it’s obvious that for industrial noise sources, a different approach must be used, which takes into account the sound absorption coefficients of the barrier, in the 1/1 or 1/3 octave band instead of DLα index.
Keywords: noise barrier, insertion loss, transmission loss, sound absorption spectrum, barrier simulation, sound source emission spectrum.
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